static PyObject *I2CDev_read(I2CDev *self, PyObject *args, PyObject *kwds) {
uint32_t n_bytes, i, addr;
PyObject *data, *byte_obj;
uint8_t *rxbuf;
if(!PyArg_ParseTuple(args, "II", &addr, &n_bytes)) {
return NULL;
}
if (self->slave_addr != addr) {
if (I2C_setSlaveAddress(self->i2c_fd, addr) < 0) {
PyErr_SetString(PyExc_IOError, "could not configure I2C interface");
return NULL;
}
self->slave_addr = addr;
}
rxbuf = malloc(n_bytes);
if (I2C_read(self->i2c_fd, (void *) rxbuf, n_bytes) < 0) {
PyErr_SetString(PyExc_IOError, "could not read from I2C device");
free(rxbuf);
return NULL;
}
data = PyList_New(0);
for (i=0; i<n_bytes; i++) {
byte_obj = PyInt_FromLong((long) rxbuf[i]);
PyList_Append(data, byte_obj);
Py_DECREF(byte_obj);
}
free(rxbuf);
return data;
}
static PyObject *I2CDev_write(I2CDev *self, PyObject *args, PyObject *kwds) {
uint32_t n_bytes, i, addr;
long byte;
PyObject *data, *byte_obj;
uint8_t *txbuf;
if(!PyArg_ParseTuple(args, "IO!", &addr, &PyList_Type, &data)) {
return NULL;
}
if (self->slave_addr != addr) {
if (I2C_setSlaveAddress(self->i2c_fd, addr) < 0) {
PyErr_SetString(PyExc_IOError, "could not configure I2C interface");
return NULL;
}
self->slave_addr = addr;
}
n_bytes = PyList_Size(data);
txbuf = malloc(n_bytes);
for (i=0; i<n_bytes; i++) {
byte_obj = PyList_GetItem(data, i);
if (!PyInt_Check(byte_obj)) {
PyErr_SetString(PyExc_ValueError,
"data list to transmit can only contain integers");
free(txbuf);
return NULL;
}
byte = PyInt_AsLong(byte_obj);
if (byte < 0) {
// Check for error from PyInt_AsLong:
if (PyErr_Occurred() != NULL) return NULL;
// Negative numbers are set to 0:
byte = 0;
}
// Just send the LSB if value longer than 1 byte:
byte &= 255;
txbuf[i] = (uint8_t) byte;
}
if (I2C_write(self->i2c_fd, (void *) txbuf, n_bytes) < 0) {
PyErr_SetString(PyExc_IOError, "could not write to I2C device");
free(txbuf);
return NULL;
}
free(txbuf);
Py_INCREF(Py_None);
return Py_None;
}
void main (void)
{
//Stop WDT
WDT_hold(__MSP430_BASEADDRESS_WDT_A__);
//Assign I2C pins to USCI_B0
GPIO_setAsPeripheralModuleFunctionInputPin(__MSP430_BASEADDRESS_PORT3_R__,
GPIO_PORT_P3,
GPIO_PIN1 + GPIO_PIN2
);
//Initialize Master
I2C_masterInit(__MSP430_BASEADDRESS_USCI_B0__,
I2C_CLOCKSOURCE_SMCLK,
UCS_getSMCLK(__MSP430_BASEADDRESS_UCS__),
I2C_SET_DATA_RATE_400KBPS
);
//Specify slave address
I2C_setSlaveAddress(__MSP430_BASEADDRESS_USCI_B0__,
SLAVE_ADDRESS
);
//Set Master in receive mode
I2C_setMode(__MSP430_BASEADDRESS_USCI_B0__,
I2C_RECEIVE_MODE
);
//Enable I2C Module to start operations
I2C_enable(__MSP430_BASEADDRESS_USCI_B0__);
//Enable master Receive interrupt
I2C_enableInterrupt(__MSP430_BASEADDRESS_USCI_B0__,
I2C_RECEIVE_INTERRUPT
);
while (1)
{
//Initiate command to receive a single character from Slave
I2C_masterSingleReceiveStart(__MSP430_BASEADDRESS_USCI_B0__);
//Enter low power mode 0 with interrupts enabled.
//Wait until character is received.
__bis_SR_register(LPM0_bits + GIE);
__no_operation();
}
}
